Pink eye causes redness in the white of the eye, some form of discharge, and a gritty or irritated feeling. But the specific symptoms vary depending on whether the cause is a virus, bacteria, or an allergy, and knowing the difference helps you figure out what to do next.
The Core Symptoms
Regardless of the cause, pink eye shares a few hallmark signs. The white of one or both eyes turns pink or red as the thin membrane covering the eye becomes inflamed. You’ll likely notice some type of discharge, whether watery, stringy, or thick. Your eyes may feel gritty or irritated, as if something small is stuck under the eyelid. Mild swelling of the eyelids is common, and the eyes often feel tender to the touch.
These symptoms can look alarming, but most cases of pink eye are mild and resolve on their own or with simple treatment. The type of discharge and a few other details can help you tell which kind you’re dealing with.
Bacterial Pink Eye
Bacterial conjunctivitis produces a thick, yellowish or greenish discharge that often causes the eyelids to crust and mat together, especially overnight. You might wake up and find it difficult to open your eyes. The redness tends to be pronounced, and eyelid swelling can be noticeable. It sometimes starts in one eye and spreads to the other within a day or two.
The CDC notes that bacterial pink eye can also cause mild pain and, occasionally, slightly decreased vision due to the discharge coating the surface of the eye. Most bacterial infections clear up within about 10 days. Antibiotic eye drops or ointment can speed recovery and reduce the chance of spreading it to others.
Viral Pink Eye
Viral conjunctivitis typically produces a watery, clear discharge rather than the thick pus associated with bacteria. It often accompanies or follows a cold, sore throat, or upper respiratory infection. One eye usually gets it first, with the second eye developing symptoms within a couple of days.
Viral pink eye can last up to two weeks, and in rare cases even longer. There’s no antibiotic treatment for it because antibiotics don’t work on viruses. Most people manage symptoms at home with cool compresses and artificial tears until the infection runs its course. You remain contagious as long as your eyes are tearing and producing discharge.
Some viral strains cause more severe forms. Adenovirus can trigger epidemic keratoconjunctivitis, a particularly intense version with significant swelling and light sensitivity. Herpes simplex virus can cause pink eye that affects only one eye and may include small blister-like lesions on the skin nearby. These forms typically need medical attention.
Allergic Pink Eye
Itching is the defining symptom. If your eyes itch intensely and you can’t stop rubbing them, allergies are the most likely cause. The discharge is watery, and both eyes are almost always affected at the same time because the allergic reaction is systemic, not a localized infection.
Allergic conjunctivitis is common in people who also have hay fever, asthma, or eczema. The conjunctiva can become puffy and swollen, sometimes taking on a boggy, fluid-filled appearance. You may also have a runny nose, sneezing, or other upper respiratory allergy symptoms. Unlike viral and bacterial pink eye, the allergic form isn’t contagious at all. It lasts as long as you’re exposed to the allergen causing it, which means it can be seasonal (pollen) or year-round (dust mites, pet dander).
How to Tell the Types Apart
The overlap between types of pink eye can make diagnosis tricky, even for clinicians. But a few patterns help narrow things down:
- Thick, colored discharge with matted eyelids: likely bacterial
- Watery discharge with a recent cold or sore throat: likely viral
- Intense itching, both eyes, with allergy history: likely allergic
- One eye only: more common with bacterial or certain viral causes like herpes
- Both eyes at once: more common with allergies
That said, the CDC acknowledges that signs and symptoms of bacterial conjunctivitis overlap significantly with other causes, which can make a firm diagnosis difficult without lab testing. When in doubt, a healthcare provider can examine the inner surface of the eyelids for specific patterns of inflammation that help distinguish the cause.
Pink Eye in Newborns
Newborns can develop eye drainage within one day to two weeks after birth. Their eyelids become puffy, red, and tender, with discharge that may be watery, bloody, or thick. The most common causes in infants are a blocked tear duct, a reaction to antibiotic eye drops given at birth, or an infection picked up during delivery.
A blocked tear duct is the most benign of these and often responds to gentle warm massage between the eye and nose. Infections in newborns, however, can be serious and need prompt evaluation, since bacteria picked up during birth can damage the eye quickly if untreated.
Contact Lens Wearers Face Extra Risks
If you wear contact lenses and develop red, irritated eyes, don’t assume it’s simple pink eye. Contact lenses can cause corneal infections (keratitis) that look similar but are more dangerous. Warning signs include eye pain that goes beyond mild irritation, blurry vision, unusual sensitivity to light, and a feeling of something stuck in your eye. These symptoms warrant removing your contacts immediately and getting evaluated the same day, because corneal infections can cause permanent vision damage if they progress.
Symptoms That Signal Something More Serious
Most pink eye is uncomfortable but harmless. However, several symptoms suggest a more serious eye condition that needs urgent care:
- Significant eye pain (not just irritation or grittiness)
- Blurred vision that doesn’t clear when you blink away discharge
- Sensitivity to light
- A persistent feeling that something is stuck in your eye
These can indicate conditions like corneal ulcers, uveitis (inflammation inside the eye), or other problems that mimic pink eye but require very different treatment. Simple conjunctivitis should not cause true pain or vision changes. If it does, something else is going on.